linux.git/arch/um/kernel, branch v6.12.80 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c 2025-11-02T13:15:22+00:00 Menglong Dong menglong8.dong@gmail.com 2025-09-17T06:09:13+00:00 cc89ac0ca52306a61db7c2d289bb9cdf1f397714 [ Upstream commit 35561bab768977c9e05f1f1a9bc00134c85f3e28 ] The include/generated/asm-offsets.h is generated in Kbuild during compiling from arch/SRCARCH/kernel/asm-offsets.c. When we want to generate another similar offset header file, circular dependency can happen. For example, we want to generate a offset file include/generated/test.h, which is included in include/sched/sched.h. If we generate asm-offsets.h first, it will fail, as include/sched/sched.h is included in asm-offsets.c and include/generated/test.h doesn't exist; If we generate test.h first, it can't success neither, as include/generated/asm-offsets.h is included by it. In x86_64, the macro COMPILE_OFFSETS is used to avoid such circular dependency. We can generate asm-offsets.h first, and if the COMPILE_OFFSETS is defined, we don't include the "generated/test.h". And we define the macro COMPILE_OFFSETS for all the asm-offsets.c for this purpose. Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 35561bab768977c9e05f1f1a9bc00134c85f3e28 ]

The include/generated/asm-offsets.h is generated in Kbuild during
compiling from arch/SRCARCH/kernel/asm-offsets.c. When we want to
generate another similar offset header file, circular dependency can
happen.

For example, we want to generate a offset file include/generated/test.h,
which is included in include/sched/sched.h. If we generate asm-offsets.h
first, it will fail, as include/sched/sched.h is included in asm-offsets.c
and include/generated/test.h doesn't exist; If we generate test.h first,
it can't success neither, as include/generated/asm-offsets.h is included
by it.

In x86_64, the macro COMPILE_OFFSETS is used to avoid such circular
dependency. We can generate asm-offsets.h first, and if the
COMPILE_OFFSETS is defined, we don't include the "generated/test.h".

And we define the macro COMPILE_OFFSETS for all the asm-offsets.c for this
purpose.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: Re-evaluate thread flags repeatedly 2025-08-20T16:30:32+00:00 Thomas Weißschuh thomas.weissschuh@linutronix.de 2025-07-04T12:34:47+00:00 0cfcc16ecd0250978ef419e35740156a85a8ea17 [ Upstream commit b9e2f2246eb2b5617d53af7b5e4e1b8c916f26a8 ] The thread flags may change during their processing. For example a task_work can queue a new signal to be sent. This signal should be delivered before returning to usespace again. Evaluate the flags repeatedly similar to other architectures. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://patch.msgid.link/20250704-uml-thread_flags-v1-1-0e293fd8d627@linutronix.de Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b9e2f2246eb2b5617d53af7b5e4e1b8c916f26a8 ]

The thread flags may change during their processing.
For example a task_work can queue a new signal to be sent.
This signal should be delivered before returning to usespace again.

Evaluate the flags repeatedly similar to other architectures.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/20250704-uml-thread_flags-v1-1-0e293fd8d627@linutronix.de
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: use proper care when taking mmap lock during segfault 2025-07-06T09:01:34+00:00 Benjamin Berg benjamin.berg@intel.com 2025-04-08T07:45:24+00:00 cf6d532de4423183952b178bac1e08e9641c844f [ Upstream commit 6767e8784cd2e8b386a62330ea6864949d983a3e ] Segfaults can occur at times where the mmap lock cannot be taken. If that happens the segfault handler may not be able to take the mmap lock. Fix the code to use the same approach as most other architectures. Unfortunately, this requires copying code from mm/memory.c and modifying it slightly as UML does not have exception tables. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250408074524.300153-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 6767e8784cd2e8b386a62330ea6864949d983a3e ]

Segfaults can occur at times where the mmap lock cannot be taken. If
that happens the segfault handler may not be able to take the mmap lock.

Fix the code to use the same approach as most other architectures.
Unfortunately, this requires copying code from mm/memory.c and modifying
it slightly as UML does not have exception tables.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20250408074524.300153-2-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: Update min_low_pfn to match changes in uml_reserved 2025-05-29T09:02:14+00:00 Tiwei Bie tiwei.btw@antgroup.com 2025-02-21T04:18:55+00:00 728945c962695ec5db95e44e9449f6b3edcccbcf [ Upstream commit e82cf3051e6193f61e03898f8dba035199064d36 ] When uml_reserved is updated, min_low_pfn must also be updated accordingly. Otherwise, min_low_pfn will not accurately reflect the lowest available PFN. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20250221041855.1156109-1-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e82cf3051e6193f61e03898f8dba035199064d36 ]

When uml_reserved is updated, min_low_pfn must also be updated
accordingly. Otherwise, min_low_pfn will not accurately reflect
the lowest available PFN.

Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250221041855.1156109-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Revert "um: work around sched_yield not yielding in time-travel mode" 2025-05-18T06:24:57+00:00 Christian Lamparter chunkeey@gmail.com 2025-05-09T09:50:39+00:00 6aac2c54762c4b0b1cbd8c7ffa365283e171bf5d This reverts commit da780c4a075ba2deb05ae29f0af4a990578c7901 which is commit 887c5c12e80c8424bd471122d2e8b6b462e12874 upstream. Reason being that the patch depends on at least commit 0b8b2668f998 ("um: insert scheduler ticks when userspace does not yield") in order to build. Otherwise it fails with: | /usr/bin/ld: arch/um/kernel/skas/syscall.o: in function `handle_syscall': | linux-6.12.27/arch/um/kernel/skas/syscall.c:43:(.text+0xa2): undefined | reference to `tt_extra_sched_jiffies' | collect2: error: ld returned 1 exit status The author Benjamin Berg commented: "I think it is better to just not backport commit 0b8b2668f998 ("um: insert scheduler ticks when userspace does not yield")" Link: https://lore.kernel.org/linux-um/8ce0b6056a9726e540f61bce77311278654219eb.camel@sipsolutions.net/ Cc: <stable@vger.kernel.org> # 6.12.y Cc: Benjamin Berg <benjamin.berg@intel.com> Signed-off-by: Christian Lamparter <chunkeey@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit da780c4a075ba2deb05ae29f0af4a990578c7901 which is
commit 887c5c12e80c8424bd471122d2e8b6b462e12874 upstream.


Reason being that the patch depends on at least commit 0b8b2668f998
("um: insert scheduler ticks when userspace does not yield") in order to
build. Otherwise it fails with:

| /usr/bin/ld: arch/um/kernel/skas/syscall.o: in function `handle_syscall':
|      linux-6.12.27/arch/um/kernel/skas/syscall.c:43:(.text+0xa2): undefined
| reference to `tt_extra_sched_jiffies'
| collect2: error: ld returned 1 exit status

The author Benjamin Berg commented: "I think it is better to just not
backport commit 0b8b2668f998 ("um: insert scheduler ticks when userspace
does not yield")"

Link: https://lore.kernel.org/linux-um/8ce0b6056a9726e540f61bce77311278654219eb.camel@sipsolutions.net/
Cc: <stable@vger.kernel.org> # 6.12.y
Cc: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
um: work around sched_yield not yielding in time-travel mode 2025-05-02T05:59:19+00:00 Benjamin Berg benjamin.berg@intel.com 2025-03-14T13:08:15+00:00 da780c4a075ba2deb05ae29f0af4a990578c7901 [ Upstream commit 887c5c12e80c8424bd471122d2e8b6b462e12874 ] sched_yield by a userspace may not actually cause scheduling in time-travel mode as no time has passed. In the case seen it appears to be a badly implemented userspace spinlock in ASAN. Unfortunately, with time-travel it causes an extreme slowdown or even deadlock depending on the kernel configuration (CONFIG_UML_MAX_USERSPACE_ITERATIONS). Work around it by accounting time to the process whenever it executes a sched_yield syscall. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250314130815.226872-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 887c5c12e80c8424bd471122d2e8b6b462e12874 ]

sched_yield by a userspace may not actually cause scheduling in
time-travel mode as no time has passed. In the case seen it appears to
be a badly implemented userspace spinlock in ASAN. Unfortunately, with
time-travel it causes an extreme slowdown or even deadlock depending on
the kernel configuration (CONFIG_UML_MAX_USERSPACE_ITERATIONS).

Work around it by accounting time to the process whenever it executes a
sched_yield syscall.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20250314130815.226872-1-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: remove copy_from_kernel_nofault_allowed 2025-04-10T12:39:25+00:00 Benjamin Berg benjamin.berg@intel.com 2025-02-10T16:09:26+00:00 5b37d2370d0c37fbf4dd7e6842cd1e0145605fbc [ Upstream commit 84a6fc378471fbeaf48f8604566a5a33a3d63c18 ] There is no need to override the default version of this function anymore as UML now has proper _nofault memory access functions. Doing this also fixes the fact that the implementation was incorrect as using mincore() will incorrectly flag pages as inaccessible if they were swapped out by the host. Fixes: f75b1b1bedfb ("um: Implement probe_kernel_read()") Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250210160926.420133-3-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 84a6fc378471fbeaf48f8604566a5a33a3d63c18 ]

There is no need to override the default version of this function
anymore as UML now has proper _nofault memory access functions.

Doing this also fixes the fact that the implementation was incorrect as
using mincore() will incorrectly flag pages as inaccessible if they were
swapped out by the host.

Fixes: f75b1b1bedfb ("um: Implement probe_kernel_read()")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20250210160926.420133-3-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: Always dump trace for specified task in show_stack 2024-12-05T13:03:03+00:00 Tiwei Bie tiwei.btw@antgroup.com 2024-11-06T10:39:33+00:00 f1ed1fbad9a841df324464c1ee4631c1b9633869 [ Upstream commit 0f659ff362eac69777c4c191b7e5ccb19d76c67d ] Currently, show_stack() always dumps the trace of the current task. However, it should dump the trace of the specified task if one is provided. Otherwise, things like running "echo t > sysrq-trigger" won't work as expected. Fixes: 970e51feaddb ("um: Add support for CONFIG_STACKTRACE") Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20241106103933.1132365-1-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0f659ff362eac69777c4c191b7e5ccb19d76c67d ]

Currently, show_stack() always dumps the trace of the current task.
However, it should dump the trace of the specified task if one is
provided. Otherwise, things like running "echo t > sysrq-trigger"
won't work as expected.

Fixes: 970e51feaddb ("um: Add support for CONFIG_STACKTRACE")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241106103933.1132365-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: Fix the return value of elf_core_copy_task_fpregs 2024-12-05T13:03:02+00:00 Tiwei Bie tiwei.btw@antgroup.com 2024-09-13T02:33:02+00:00 a60368b192a3ca79db34c9735a21e9b2a1b6f098 [ Upstream commit 865e3845eeaa21e9a62abc1361644e67124f1ec0 ] This function is expected to return a boolean value, which should be true on success and false on failure. Fixes: d1254b12c93e ("uml: fix x86_64 core dump crash") Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20240913023302.130300-1-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 865e3845eeaa21e9a62abc1361644e67124f1ec0 ]

This function is expected to return a boolean value, which should be
true on success and false on failure.

Fixes: d1254b12c93e ("uml: fix x86_64 core dump crash")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20240913023302.130300-1-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
um: Fix potential integer overflow during physmem setup 2024-12-05T13:03:02+00:00 Tiwei Bie tiwei.btw@antgroup.com 2024-09-16T04:59:48+00:00 a9c95f787b88b29165563fd97761032db77116e7 [ Upstream commit a98b7761f697e590ed5d610d87fa12be66f23419 ] This issue happens when the real map size is greater than LONG_MAX, which can be easily triggered on UML/i386. Fixes: fe205bdd1321 ("um: Print minimum physical memory requirement") Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20240916045950.508910-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a98b7761f697e590ed5d610d87fa12be66f23419 ]

This issue happens when the real map size is greater than LONG_MAX,
which can be easily triggered on UML/i386.

Fixes: fe205bdd1321 ("um: Print minimum physical memory requirement")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20240916045950.508910-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>